(1) Field of the Invention
The present invention relates to a current detection device for detecting a current of batteries, generators and the like mounted on an automobile, and more specifically to a current detection device in which a magentic-sensitive element (such as a Hall element) is disposed in an air gap of a magnetic core to detect a current, and a core for detection of a magnetic flux.
(2) Description of the Prior Art
A device has been heretofore known in which for example, a gap is provided in a ferrite core, a magnetic sensitive element such as a Hall element is disposed therein, and a value of current to be detected is detected from an output of said magnetic-sensitive element. More specifically, when a current to be detected flows into a coil (or an electric wire inserted into a hollow portion) wound around the ferrite core, a magnetic field is generated according to a value of said current, and the magnetic field is detected by the magnetic-sensitive element whereby the current value thereof can be detected. In this case, the output of the magnetic-sensitive element is small, and accordingly, amplification processing and other signal processings are required. To this end, a construction has been often practically used wherein circuit elements for these signal processings and the aforesaid magnetic-sensitive element are packaged on a printed substrate, the entire body of which is accommodated within a case.
However, in the current detector constructed as described above, it is difficult to positively locate the magnetic-sensitive element into the gap of the core, and there is a problem in that the assembling workability is bad. Further problems are that the magnetic-sensitive element is worn and the core is removed from the case.
Furthermore, when the core is greatly deformed or the dimension of the air gap is large, it becomes difficult to assure the locating accuracy of the magnetic-sensitive element, which also entails a difficulty in maintaining the accuracy of measurement.